;(function (global) {
/*
Copyright (c) 2010 Remy Sharp, http://remysharp.com

Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:

The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/

if ("EventSource" in global) return;

var reTrim = /^(\s|\u00A0)+|(\s|\u00A0)+$/g;

var EventSource = function (url) {
  var eventsource = this,  
      interval = 500, // polling interval  
      lastEventId = null,
      cache = '';

  if (!url || typeof url != 'string') {
    throw new SyntaxError('Not enough arguments');
  }

  this.URL = url;
  this.readyState = this.CONNECTING;
  this._pollTimer = null;
  this._xhr = null;
  
  function pollAgain(interval) {
    eventsource._pollTimer = setTimeout(function () {
      poll.call(eventsource);
    }, interval);
  }
  
  function poll() {
    try { // force hiding of the error message... insane?
      if (eventsource.readyState == eventsource.CLOSED) return;

      // NOTE: IE7 and upwards support
      var xhr = new XMLHttpRequest();
      xhr.open('GET', eventsource.URL, true);
      xhr.setRequestHeader('Accept', 'text/event-stream');
      xhr.setRequestHeader('Cache-Control', 'no-cache');
      // we must make use of this on the server side if we're working with Android - because they don't trigger 
      // readychange until the server connection is closed
      xhr.setRequestHeader('X-Requested-With', 'XMLHttpRequest');

      if (lastEventId != null) xhr.setRequestHeader('Last-Event-ID', lastEventId);
      cache = '';
    
      xhr.timeout = 50000;
      xhr.onreadystatechange = function () {
        if (this.readyState == 3 || (this.readyState == 4 && this.status == 200)) {
          // on success
          if (eventsource.readyState == eventsource.CONNECTING) {
            eventsource.readyState = eventsource.OPEN;
            eventsource.dispatchEvent('open', { type: 'open' });
          }

          var responseText = '';
          try {
            responseText = this.responseText || '';
          } catch (e) {}
        
          // process this.responseText
          var parts = responseText.substr(cache.length).split("\n"),
              eventType = 'message',
              data = [],
              i = 0,
              line = '';
            
          cache = responseText;
        
          // TODO handle 'event' (for buffer name), retry
          for (; i < parts.length; i++) {
            line = parts[i].replace(reTrim, '');
            if (line.indexOf('event') == 0) {
              eventType = line.replace(/event:?\s*/, '');
            } else if (line.indexOf('retry') == 0) {                           
              retry = parseInt(line.replace(/retry:?\s*/, ''));
              if(!isNaN(retry)) { interval = retry; }
            } else if (line.indexOf('data') == 0) {
              data.push(line.replace(/data:?\s*/, ''));
            } else if (line.indexOf('id:') == 0) {
              lastEventId = line.replace(/id:?\s*/, '');
            } else if (line.indexOf('id') == 0) { // this resets the id
              lastEventId = null;
            } else if (line == '') {
              if (data.length) {
                var event = new MessageEvent(data.join('\n'), eventsource.url, lastEventId);
                eventsource.dispatchEvent(eventType, event);
                data = [];
                eventType = 'message';
              }
            }
          }

          if (this.readyState == 4) pollAgain(interval);
          // don't need to poll again, because we're long-loading
        } else if (eventsource.readyState !== eventsource.CLOSED) {
          if (this.readyState == 4) { // and some other status
            // dispatch error
            eventsource.readyState = eventsource.CONNECTING;
            eventsource.dispatchEvent('error', { type: 'error' });
            pollAgain(interval);
          } else if (this.readyState == 0) { // likely aborted
            pollAgain(interval);
          } else {
          }
        }
      };
    
      xhr.send();
    
      setTimeout(function () {
        if (true || xhr.readyState == 3) xhr.abort();
      }, xhr.timeout);
      
      eventsource._xhr = xhr;
    
    } catch (e) { // in an attempt to silence the errors
      eventsource.dispatchEvent('error', { type: 'error', data: e.message }); // ???
    } 
  };
  
  poll(); // init now
};

EventSource.prototype = {
  close: function () {
    // closes the connection - disabling the polling
    this.readyState = this.CLOSED;
    clearInterval(this._pollTimer);
    this._xhr.abort();
  },
  CONNECTING: 0,
  OPEN: 1,
  CLOSED: 2,
  dispatchEvent: function (type, event) {
    var handlers = this['_' + type + 'Handlers'];
    if (handlers) {
      for (var i = 0; i < handlers.length; i++) {
        handlers[i].call(this, event);
      }
    }

    if (this['on' + type]) {
      this['on' + type].call(this, event);
    }
  },
  addEventListener: function (type, handler) {
    if (!this['_' + type + 'Handlers']) {
      this['_' + type + 'Handlers'] = [];
    }
    
    this['_' + type + 'Handlers'].push(handler);
  },
  removeEventListener: function (type, handler) {
    var handlers = this['_' + type + 'Handlers'];
    if (!handlers) {
      return;
    }
    for (var i = handlers.length - 1; i >= 0; --i) {
      if (handlers[i] === handler) {
        handlers.splice(i, 1);
        break;
      }
    }
  },
  onerror: null,
  onmessage: null,
  onopen: null,
  readyState: 0,
  URL: ''
};

var MessageEvent = function (data, origin, lastEventId) {
  this.data = data;
  this.origin = origin;
  this.lastEventId = lastEventId || '';
};

MessageEvent.prototype = {
  data: null,
  type: 'message',
  lastEventId: '',
  origin: ''
};

if ('module' in global) module.exports = EventSource;
global.EventSource = EventSource;
 
})(this);
